Saúl Martinez-Horta

Saúl Martinez-Horta
Hospital de la Santa Creu i Sant Pau · Neurology Services

Doctor of Medicine

About

117
Publications
16,500
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1,590
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Introduction
Saul Martinez-Horta is Neuropsychologist at the Movement Disorders Unit of the Department of Neurology at Sant Pau Hospital and researcher of the Parkinson’s disease and other movement disorders research group from the Biomedical Research Institute Sant Pau. He is also the coordinator of the Working Group in Neuropsychology of Movement Disorders of the Official Catalan College of Psychology and co-leader of the Cognitive Phenotype Working Group of the European Huntington’s Disease Network. He develops his work in Parkinson’s and Huntington’s disease with main research focused on the cognitive and behavioral aspects associated with basal ganglia disorders.
Additional affiliations
September 2008 - present
IR-Sant Pau - Sant Pau Institute of Biomedical Research
Position
  • Researcher
January 2008 - present
Hospital de la Santa Creu i Sant Pau
Position
  • Neuropsychologist

Publications

Publications (117)
Article
Full-text available
Background Patients with Huntington’s disease (HD) exhibit a variable predominance of cognitive, behavioral and motor symptoms. A specific instrument focusing on the impact of cognitive impairment in HD over functional capacity is lacking. Objective To address the need for a brief and specifically developed HD questionnaire able to capture functio...
Article
Background: Huntington's disease (HD) is a neurodegenerative disorder characterized by cognitive, motor, and neuropsychiatric manifestations. Oxytocin is a neuropeptide studied for its role as a neuromodulator regulating multiple behaviors linked to social cognition. Genetic variation of oxytocin receptor (OXTR) might interact in the etiology and...
Article
Full-text available
Background: Apathy is highly prevalent and disabling in Parkinson's disease (PD). Pharmacological options for its management lack sufficient evidence. Objective: We studied the effects of safinamide on apathy in PD. Methods: Prospective, 24-week, two-site, randomized, double-blind, placebo-controlled, parallel-group exploratory study in non-de...
Article
Background: Apathy represents a core neuropsychiatric symptom in Parkinson's disease (PD). As there is currently no established effective treatment for apathy in PD, further investigating the biological origin of this symptom is needed to design novel therapeutic strategies. Among the multiple neurotransmitter alterations that have been associated...
Article
Full-text available
Mild cognitive impairment in Parkinson’s disease (PD-MCI) is associated with consistent structural and functional brain changes. Whether different approaches for diagnosing PD-MCI are equivalent in their neural correlates is presently unknown. We aimed to profile the neuroimaging changes associated with the two endorsed methods of diagnosing PD-MCI...
Article
Full-text available
Purpose Huntington’s disease (HD) is a monogenic neurodegenerative disease with no effective treatment currently available. The pathological hallmark of HD is the aggregation of mutant huntingtin in the medium spiny neurons of the striatum, leading to severe subcortical atrophy. Cortical degeneration also occurs in HD from its very early stages, al...
Article
Background Blood homocysteine appears to be increased in Parkinson's disease (PD) and may play a role in the development and progression of this disorder. However, the specific contribution of abnormal homocysteine levels to cortical degeneration in PD remains elusive. Objective To characterize the cortical structural correlates of homocysteine le...
Article
Full-text available
Background Identifying modifiable risk factors for cognitive impairment in the early stages of Parkinson’s disease (PD) and estimating their impact on cognitive status may help prevent dementia (PDD) and the design of cognitive trials. Methods Using a standard approach for the assessment of global cognition in PD and controlling for the effects of...
Article
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Background: Huntington's disease is a neurodegenerative disorder characterized by clinical alterations in the motor, behavioral, and cognitive domains. However, the structure and disruptions to large-scale brain cognitive networks have not yet been established. Objective: We aimed to profile changes in large-scale cognitive networks in premanife...
Article
Full-text available
Female Huntington’s disease (HD) patients have consistently shown a faster clinical worsening than male, but the underlying mechanisms responsible for this observation remain unknown. Here, we describe how sex modifies the impact of neurodegeneration on brain atrophy and clinical severity in HD. Cerebrospinal fluid neurofilament light chain (NfL) l...
Article
Full-text available
Green oat extracts have been used for centuries in traditional medicine in view of their supposed beneficial effects on cognition and mood. Recently, a specific green oat formulation (Neuravena ® ) showed to have significant bioactive compounds potentially associated with the enhancement of processing speed, working memory and attention. The main a...
Article
Background: Arithmetic word-problem solving depends on the interaction of several cognitive processes that may be affected early in the disease in gene-mutation carriers for Huntington's disease (HD). Objective: Our goal was to examine the pattern of performance of arithmetic tasks in premanifest and manifest HD, and to examine correlations betw...
Article
Full-text available
Background Although several progressive supranuclear palsy (PSP) phenotypes have recently been described, studies identifying cognitive and neuropsychiatric differences between them are lacking. Methods An extensive battery of cognitive and behavioural assessments was administered to 63 PSP patients, 25 PD patients with similar sociodemographic cha...
Conference Paper
Background HD is a suitable model to monitor the whole neurodegeneration process. Huntington’s disease (HD) affects primarily the striatum, but loss of white matter (WM) integrity and iron homeostasis disruption have been also described. These anomalies together with metabolite profiles could unveil the pathophysiologic mechanisms involved. Aims T...
Conference Paper
Background While Huntington’s disease (HD) is diagnosed by motor onset, psychiatric disturbances may present years prior to formal diagnosis, bearing a significant burden on daily functioning. However, there is great inter-individual heterogeneity in psychiatric expression and evolution over time. As such, the present study strives to discern longi...
Article
Background: Empathy is a multidimensional construct and a key component of social cognition. In Huntington's disease (HD), little is known regarding the phenomenology and the neural correlates of cognitive and affective empathy, and regarding how empathic deficits interact with other behavioral and cognitive manifestations. Objective: To explore...
Article
Full-text available
Aim To determine if there are differences in terms of neurophysiology and neurocognitive functioning a group of type 1 diabetes (T1D) patients in terms of hypoglycaemia awareness. Methods 27 patients with T1D were classified according to Clarke score as having impaired awareness of hypoglycaemia (IAH; n=11) or normal awareness to hypoglycaemia (NA...
Article
Background: Apathy, a common neuropsychiatric disturbance in Huntington's disease (HD), is subserved by a complex neurobiological network. However, no study has yet employed a whole-brain approach to examine underlying regional vulnerabilities that may precipitate apathy changes over time. Objectives: To identify whole-brain gray matter volume (...
Article
Hallucinations in Parkinson’s disease (PD) are disturbing and frequent non-motor symptoms and constitute a major risk factor for psychosis and dementia. We report a robotics-based approach applying conflicting sensorimotor stimulation, enabling the induction of presence hallucinations (PHs) and the characterization of a subgroup of patients with PD...
Article
Cognitive deficits are common in Parkinson's disease (PD), with some PD patients meeting criteria for mild cognitive impairment (MCI). An unaddressed question is whether linguistic prediction is preserved in PD. This ability is nowadays deemed crucial in achieving fast and efficient comprehension, and it may be negatively impacted by cognitive dete...
Article
Objectives To explore and quantify systematically the ocular abnormal movements present in progressive supranuclear palsy (PSP) from the early stages, to assess the ability of this standardized examination in the differential diagnosis of PSP from Parkinson’s disease (PD), and to compare in more detail oculomotor disturbances between PSP variants....
Article
Introduction Huntington’s disease is a severe neurodegenerative disorder with no effective treatment. Minimally-invasive biomarkers such as blood neurofilament light chain (NfL) in HD are therefore needed to quantitatively characterize neuronal loss. NfL levels in HD are known to correlate with disease progression and striatal atrophy, but whether...
Article
Full-text available
In Huntington’s disease (HD), irritability and aggressive behavior represent highly prevalent and disabling neuropsychiatric symptoms. However, their structural brain correlates have not been extensively explored. Here, we rated the severity of irritability and aggression (IAs) using the Problem Behaviors Assessment for HD (PBA-s) in 31 early HD pa...
Article
Striatal dopamine transporter (DAT) uptake assessment through I¹²³-Ioflupane Single-Pphoton Emission Computed Tomography (SPECT) provides valuable information about the dopaminergic denervation occurring in Parkinson's disease (PD). However, little is known about the clinical or biological relevance of extrastriatal DAT uptake in PD. Here, from the...
Preprint
Full-text available
Cognitive deficits are common in Parkinson’s disease (PD), with some PD patients meeting criteria for mild cognitive impairment (MCI). An unaddressed question is whether linguistic prediction is preserved in PD. This ability is nowadays deemed crucial in achieving fast and efficient comprehension, and it may be negatively impacted by cognitive dete...
Article
Context Type 1 Diabetes (T1D) is associated with an increased risk of cognitive decline, where severe hypoglycaemia (SH) and impaired awareness of hypoglycaemia (IAH) may play a role. While there is evidence of a possible association between IAH and brain damage, the potential brain changes remain poorly characterized by magnetic resonance imaging...
Article
Full-text available
Background Chronic levodopa treatment in Parkinson’s disease (PD) may promote undesirable motor and non-motor fluctuations. Compared to chronic oral levodopa treatment, continuous infusion of levodopa/carbidopa intestinal gel (LCIG) in advanced PD reduces motor fluctuations. However, differences in their effect on acute non-motor changes were not f...
Article
Background and purpose Well‐structured hallucinations in Parkinson’s disease (PD) are associated with poor prognosis and dementia. However, the predictive value of minor psychotic phenomena in cognitive deterioration is not well known. Cross‐sectional studies have shown that PD patients with minor hallucinations have more severe cortical atrophy th...
Article
About 20% of type 1 diabetes (T1D) patients have impaired awareness of hypoglycemia (IAH). IAH represents a risk factor for severe and recurrent hypoglycemic events, which can lead to brain damage. As no effective treatments are currently available to prevent IAH in this population, characterizing the set of brain alterations associated with IAH ma...
Article
Full-text available
Background: Huntington's disease (HD) is a fatal genetic neurodegenerative disorder with no effective treatment currently available. Progressive basal ganglia and whole-brain atrophy and concurrent cognitive deterioration are prototypical aspects of HD. However, the specific patterns of brain atrophy underlying cognitive impairment of different se...
Article
Full-text available
Background Impulse control disorders (ICD) are a common and disrupting complication of Parkinson’s disease (PD) treatment. Although their relationship with dopaminergic activity is well studied, their brain metabolic correlates are mostly unknown. Methods In this work we studied brain metabolism using brain ¹⁸F-FDG-PET. We performed a case-control...
Article
Full-text available
Introduction Impaired awareness of hypoglycemia (IAH) is a common complication in patients with type-1 diabetes (T1D). IAH is a major risk factor for severe hypoglycemic events, leading to adverse clinical consequences and cerebral damage. Non-invasive, cost-effective, and logistically efficient biomarkers for this condition have not been validated...
Preprint
Full-text available
Hallucinations in Parkinson's disease (PD) are one of the most disturbing non-motor symptoms, affect half of the patients, and constitute a major risk factor for adverse clinical outcomes such as psychosis and dementia. Here we report a robotics-based approach, enabling the induction of a specific clinically-relevant hallucination (presence halluci...
Article
Full-text available
Background Cognitive impairment is an essential feature of Huntington’s disease (HD) and dementia is a predictable outcome in all patients. However, validated instruments to assess global cognitive performance in the field of HD are lacking.Objectives We aimed to explore the utility of the Parkinson’s disease-Cognitive Rating Scale (PD-CRS) for the...
Article
Full-text available
Introduction: Memory alterations are common in Parkinson’s disease (PD) patients but the mechanisms involved in these deficits remain poorly understood. The study aims to explore the profile of episodic memory deficits in non-demented early PD patients. Methods: We obtained neurological, cognitive and behavioral data from 114 PD patients and 41 he...
Article
Background Impulsivity is an aspect of personality and a major component of multiple neuropsychiatric conditions. In Parkinson’s disease, it has been associated with the expression of impulse control disorders, a highly prevalent non‐motor complication. Even though multiple tests of impulsivity have been used in this context, the impact of test cho...
Article
Introduction Cognitive impairment and dementia are highly prevalent non-motor complications in Parkinson's disease (PD) with deleterious consequences for patients and caregivers. With no treatment currently available, finding and validating minimally-invasive biomarkers of neurodegeneration in this population represents an urgent need for clinical...
Article
We have discovered an error in the Table in our article “Depression as a Risk Factor for Impulse Control Disorders in Parkinson Disease.” The Table contains a typographical error. In the column headed “PD-Not Depressed,” the number of women should be 101 (not 104). The associated percentages and statistics were based on the correct number and there...
Article
Background: The C allele of the rs11136000 genetic variant of the clusterin gene has been associated with increased risk of Alzheimer's disease. However, a comprehensive characterization of the role of this genetic variant in early cognitive deterioration in PD is lacking. Methods: Using the Parkinson's Progression Markers Initiative database, w...
Article
Progressive striatal atrophy has long been considered the pathological hallmark of Huntington’s disease (HD), but is it now recognized that malfunction and degeneration of posterior-cortical territories are also prominent characteristics of the disease. The limited knowledge about the functional impact of these posterior-cortical changes could be p...
Article
Cognitive impairment and dementia in Parkinson's disease (PD) are highly disabling non-motor symptoms with no effective treatment currently available. As cortical degeneration is thought to be involved in the development of these comorbidities, novel imaging biomarkers capable of detecting early cortical deterioration are needed. Recently, an incre...
Article
Full-text available
Background and purpose: Huntington disease is a devastating genetic neurodegenerative disorder for which no effective treatment is yet available. Although progressive striatal atrophy is its pathologic hallmark, concomitant cortical deterioration is assumed to occur, but it is poorly characterized. Our objective was to study the loss of cortical i...
Article
Objectives: To longitudinally evaluate the role of depression in the development of impulse control disorders (ICD) in Parkinson's disease (PD) patients. Methods: Using data from the Parkinson's Progression Markers Initiative (PPMI) we included PD patients without ICD at baseline according to the Questionnaire for Impulsive-Compulsive Disorders...
Article
Full-text available
Understanding on the clinical features and neural mechanisms leading to cognitive impairment and dementia in Parkinson’s disease (PD) has notably increased. At time of diagnosis, nearly all PD patients present some degree of cognitive impairment not enough severe as to significantly affect functional independence. However, even mild cognitive chang...
Article
Full-text available
Background: Apathy is the neuropsychiatric syndrome that correlates most highly with Huntington's disease progression, and, like early patterns of neurodegeneration, is associated with lesions to cortico-striatal connections. However, due to its multidimensional nature and elusive etiology, treatment options are limited. Objectives: To disentang...
Article
Introduction: Cognitive impairment and behavioral disturbances are common findings in Parkinson’s disease (PD). Despite initially being considered late complications of the disease, it is currently accepted that almost all PD patients will exhibit cognitive and behavioral abnormalities from the early and even the premotor stages of the disease. Are...
Article
The brain-derived neurotrophic factor (BDNF) val66met polymorphism has been suggested to modulate cognitive deterioration in Parkinson's disease (PD). In particular, the val/val genotype has been recently suggested to increase the risk of cognitive decline in this population. However, to date, little is known about the underlying brain alterations...
Article
Full-text available
Huntington's disease (HD) is a genetic neurodegenerative disease which involves a triad of motor, cognitive and psychiatric disturbances. However, there is great variability in the prominence of each type of symptom across individuals. The neurobiological basis of such variability remains poorly understood but would be crucial for better tailored t...
Article
Patients with borderline personality disorder (BPD) present dysfunctions of the default mode network (DMN). Mindfulness training has proven effective to improve the symptoms of BPD. The present study examines the effect of mindfulness training on BPD symptomatology and DMN activity during the performance of a working memory task in patients with BP...
Article
Full-text available
Purpose Huntington’s disease (HD) is a fatal neurodegenerative disorder with no effective treatment currently available. Although the pathological hallmark of HD is massive striatal atrophy, it has been suggested that cortical deterioration may concomitantly occur and play a major role in the patient’s functional independence. Our objective was to...
Article
Full-text available
Cognitive decline is a major disabling feature in Parkinson's disease (PD). Multimodal imaging studies have shown functional disruption in neurocognitive networks related to cognitive impairment. However, it remains unknown whether these changes are related to gray matter loss, or whether they outline network vulnerability in the early stages of co...
Article
Objective: Because patients homozygous for Huntington disease (HD) receive the gain-of-function mutation in a double dose, one would expect a more toxic effect in homozygotes than in heterozygotes. Our aim was to investigate the phenotypic differences between homozygotes with both alleles ≥36 CAG repeats and heterozygotes with 1 allele ≥36 CAG rep...
Article
The COMT Val¹⁵⁸Met polymorphism has recently been identified as a predictor for cognitive decline in Parkinson’s disease (PD). However, it remains unknown whether an early brain structural compromise could be involved in this clinical association. Here, in a cohort of 120 cognitively preserved de novo PD patients from the Parkinson’s Progression Ma...
Article
Background Minor hallucinations and well‐structured hallucinations are considered in the severity continuum of the psychotic spectrum associated with Parkinson's disease. Although their chronological relationship is largely unknown, the spatial patterns of brain atrophy in these 2 forms of hallucinations partially overlap, suggesting they share sim...
Article
Background: Cognitive decline in Parkinson's disease (PD) is a highly prevalent condition with no effective treatment. Cortical atrophy is thought to promote its development but to design optimal therapeutic approaches in this clinical setting we need to understand the physiopathological mechanisms leading to this disorder. Objective: To charact...
Article
Background: The frequency of late-onset Huntington's disease (>59 years) is assumed to be low and the clinical course milder. However, previous literature on late-onset disease is scarce and inconclusive. Objective: Our aim is to study clinical characteristics of late-onset compared to common-onset HD patients in a large cohort of HD patients fr...
Article
The role of cerebrospinal fluid (CSF) biomarkers such as CSF α-synuclein and CSF tau in predicting cognitive decline in Parkinson's disease (PD) continues to be inconsistent. Here, using a cohort of de novo PD patients with preserved cognition from the Parkinson's Progression Markers Initiative (PPMI), we show that the SNCA rs356181 single nucleoti...
Article
Objective: Normalization to an appropriate reference region in F-FDG PET imaging may enhance diagnostic performance in Huntington disease (HD). We aimed to identify stable brain areas that could be used to model neurometabolic degeneration in HD correlating imaging (SUVrvalues at the basal ganglia [BBGG]) and clinical parameters (disease burden sc...
Article
A cognitive stimulating lifestyle has been observed to confer cognitive benefits in multiple neurodegenerative diseases. However, the underlying neurobiological basis of this phenomenon remains unclear. Huntington's disease can provide a suitable model to study the effects and neural mechanisms of cognitive engagement in neurodegeneration. In this...
Article
Full-text available
Introduction: Impulse control disorders (ICDs) are a common complication of Parkinson's disease (PD) receiving dopamine agonist (DAA) Impulsivity is considered an underlying mechanism but evidence of this relationship is scarce. To explore the relationship between impulsivity and the presence and severity of ICD in PD. Methods: Prospective cross-se...
Article
Full-text available
The present study investigated language inhibition and cross-language interference as two possible mechanisms of bilingual language control (BLC) that can be affected by Huntington’s disease (HD), a neurodegenerative disease (ND) affecting the striatum. To this aim, the study explored the performance of pre-symptomatic and early-stage HD patients i...
Article
Introduction: Bilingualism exerts neuroprotective effects against neurodegeneration. In Huntington's disease (HD), the systems involved in bilingual control show early compromise, but the effect of bilingualism on the course of HD is unknown. Methods: We addressed the impact of livelong use of bilingualism on the clinical features, brain structu...
Conference Paper
Along with motor and cognitive deterioration, neuropsychiatric symptoms form a common feature of Huntington’s disease. Of these, apathy has been shown to most highly correlate with disease progression, often emerging prior to clinical diagnosis. However, due to the multidimensional nature of apathy, its elusive etiology, and the lack of operative d...